1. Field of the Invention
The present invention relates to a photographic printing method, and in particular, a photographic printing method in which film image frames are photometrically measured, an amount of printing exposure is automatically determined based on photometric values, and the image frames are printed onto photographic paper.
2. Description of the Related Art
In an automatic printer, in which images recorded on a film are automatically printed onto photographic paper, each image of the film is photometrically measured, and a integral transmission density of the entire image surface of each image frame is calculated. Based on the difference between this integral transmission density and a reference density (e.g., an bull's eye negative density), slope control, color correction, and the like are effected, the amount of printing exposure is determined for each image, and printing processing is effected. Accordingly, dispersion of exposures at the time of photographing and color failure are corrected, and a print with appropriate density and color balance can be obtained. The average value of integral transmission densities of many images may be used as a reference density.
There are various known techniques for improvement, upon the above such as the so-called multipoint photometric method (also called the dividing photometric method, the evaluating photometric method, the multi-pattern photometric method, and the multi-photometric method), in which different areas of a photographed subject are photometrically measured by a plurality of photometric elements, and the exposure is automatically set by a camera (e.g., Japanese Patent Laid-Open No. 57-42026, Japanese Patent Laid-Open No. 1-280737, Japanese Patent Laid-Open No. 2-84628). With this method, the precision of the exposure greatly improves, and the dispersion of exposures of each of various scenes is greatly decreased.
However, when a film, which has been taken by a camera which automatically determines the exposure as above, is set in an automatic printer utilizing a multipoint photometric method and printing processing is effected, the amount of printing exposure for each image is determined, based on the integral transmission density of each image. Therefore, an amount of printing exposure, which excessively corrects image frames which have little dispersion of exposures, is set. Accordingly, having the appropriate density may not be obtained in each print. In a camera which locks exposure when the main subject is focused, the image is photographed at an exposure at which the main subject is the reference. Therefore, the correction amount of the printing exposure with regard to the dispersion of the exposures is small. However, it is difficult for the automatic printer to determine what the main subject of an image is. The amount of printing exposure is calculated based, as described above, on the integral transmission density of the image, but the integral transmission density is effected by the density of the background. For example, if the density of the background is high, it will be determined that the image has been over-exposed and there will be excessive correction in order to increase the amount of printing exposure. As a result, the density of the main subject of the resulting print will be higher than the desired density that was expected.